After an acrimonious campaign, polls opened in Pakistan on Wednesday to elect the country's third straight civilian government, a first for this majority Muslim nation that has been directly or indirectly ruled by its military for most of its 71-year history. More than 30 political parties have fielded their candidates for the elections.

Lashkar-e-Taiba chief and head of the Pakistani religious party Jamaat-ud-Dawa, Hafiz Saeed affixes his thumb impression before casting a vote in Lahore. (AP/PTI)

Pakistan Tehreek-e-Insaf party chief and Pakistani politician, Imran Khan, casts his vote at a polling station in Islamabad.

Pakistani voters pose with their national identity cards waiting in a queue to cast their votes in Rawalpindi.

A supporter of Pakistani former prime minister Nawaz Sharif arrives at a polling station to cast his vote in Lahore. (AP)

Women, clad in burqas, stand in line to cast their ballot at a polling station in Peshawar.

A Pakistani voter affixes his thumb impression ahead of voting in Rawalpindi. (AP)

According to a survey of polls computed by Gallup Pakistan, Imran Khan's PTI and the PML-N are running "neck and neck", with the PTI ahead nationally and the PML-N ahead in the crucial province of Punjab. (AP)